The present invention relates to a method for traffic engineering and to an ingress router.
Such a method is already known in the art, e.g. from RFC3270of the IETF working group.
Therein the basic principles for queuing packets according to their service class, in this document called a Behavior Aggregate and abbreviated with BA, within ingress routers of a packet network such as the Internet, is described. This is supplemented by what is described in another RFC at the same webpage, being RFC3290, in which a BA-classifier and the different queues are further described, the BA-classifier being the device within the ingress source router which determines in which queue a packet will be temporarily stored. Furthermore RFC 3031 from the same webpage describes the concept of having dedicated tunnels to which traffic can flow.
State of the art Internet ingress routers are thus adapted to discriminate incoming packets into those following the “normal” IP-route, and those intended to follow the tunnel, in the Internet case being mostly MPLS-tunnels. Moreover, these state of the art routers can further discriminate between the different service classes of the packets such that, per egress interface of such an ingress router, several queues are present. These queues can for instance consist of Diffserv queues in the Internet, and being one per service class, in which all packets intended to be transported over that interface are classified in accordance to their service class. It is important to recognize that in this case no distinction is made between the “normal” IP-traffic, and the “tunnel” MPLS-traffic, in other words, both traffic type packets are stored in the same queue if these have the same service category.
This state of the art method and ingress router however has the drawback that the MPLS tunnel can be easily overloaded with traffic, since the estimated bandwidth for this tunnel, which is initially communicated by the network administrator and which is reserved for the specific tunnel, is just a prediction which may prove not be very realistic, and which may give rise to congestion problems. In the present situation no traffic engineering solution is thus available for the traffic intended for the MPLS-tunnels.